Come funziona il DNS: domini, indirizzi IP, resolver e record spiegati semplice

In this video, we'll see how DNS works, the system that transforms a domain like www.example.com into an IP address that can be reached by a browser. In the first episode, we learned how to read a URL. Now, let's dive deeper and answer a fundamental question: when we type a domain into a browser, how does the computer know which server to contact? DNS, or Domain Name System, is often described as the "Internet's address book." This is a useful metaphor, but it's incomplete: in reality, DNS is a distributed, hierarchical system made up of DNS resolvers, DNS caches, root servers, TLD servers, authoritative nameservers, DNS records, and TTLs. In the video, we'll see: why the Internet uses IP addresses and not just human-readable names; what is DNS resolution; what role does the DNS resolver play? how the root server, TLD, and authoritative nameserver hierarchy work; What are A, AAAA, CNAME, MX, TXT, and NS records; What is the TTL for? Why sometimes a site works on one network but not another; Why DNS is also important for web security. Understanding DNS helps users, developers, and those interested in cybersecurity better understand web problems: sites that don't load, DNS propagation, stale caches, subdomains, email, cloud providers, CDNs, and incorrect configurations. If you're interested in web development, cybersecurity, DNS, networking, HTTP, HTTPS, domains, IP addresses, and programming, and want to better understand what happens when you launch a website, this episode is designed to start with the basics. Chapters 00:26 From Name to Address 01:18 It's Not a Single Column 01:51 Before the Page 02:27 First Question: Do You Already Know This? 03:13 The Resolver 04:02 The DNS Hierarchy 05:10 The Final Answer 05:50 The Complete Journey 06:39 TTL: In-Time Responses 08:02 Record Types 08:56 An Architecture Map 09:29 If DNS Fails 10:07 Mental Debugging 11:28 Before Login 12:33 Next Episode --- Are you interested in tutorials on programming, web development, Linux, security, operating systems, and open source software? Subscribe to our channel: https://www.youtube.com/@scrivocodice... You can take our courses on Udemy: https://www.udemy.com/user/scrivocodice/ Follow us here too: YouTube: https://www.youtube.com/@scrivocodice... Facebook:   / 61559544457789   TikTok:   / scrivocodice   LinkedIn:   / scrivo-codice-640796220   If you have any questions about DNS, domains, DNS records, resolvers, TTL, DNS cache, or propagation issues, leave a comment below the video. See you in the next video! #DNS #DomainNameSystem #WebDevelopment #ComputerSecurity #CyberSecurity #Networking #IPAddress #Domains #DNSResolver #DNSCache #TTL #DNSRecord #HTTPS #HTTP #WebSecurity #Programming #ComputerScience #WritingCode